Many industrial installations demand equipment capable automatically of controlling the supply of gases and fluids to certain equipment. The manufacture of integrated circuits generally includes several processes such as, for example, vapor deposition, in which a variety of gases is conveyed to a reaction chamber in which a semiconductor substrate is confined. The temperature and pressure at which the various layers of materials developed in order to create three-dimensional models of integrated circuits are deposited are carefully controlled in this space.
All the substances carried into and out of the reaction chamber have to be constantly monitored because the proportions of the various reagents that make up the vapor atmosphere ultimately determine the physical dimensions of the elements which together will make up a simple vast electrical circuit on a minuscule piece of silicon, notably transistors, capacitors and resistors. One of the greatest causes of incorrect operation of integrated circuits can be attributed to microscopic dust particles contaminating the working area in which the circuit is manufactured. A minuscule foreign body can damage a very expensive circuit and render it unusable. To protect against such particulate contamination, the manufacturers of semiconductors manufacture their products in a protected “clean room” environment.
The air admitted to a clean room is first of all filtered, thus almost entirely eliminating the undesired dust particles. The technicians who work in these environments wear special masks and clothing that prevent the introduction of substances that would be damaging to their meticulous work. The costs associated with the maintenance and correct running of this highly specialized environment are considerable. Hence, any clean room space has to be used as efficiently as possible.
Aside from this critical requirement, the chemical products used have to be distributed with great care. The liquid chemical products and specialty gases used in the semiconductors industry are often toxic. The devices chosen for distributing these potentially dangerous products have to provide reliable use, protected against corrosion or leakage.
In a conventional gas distribution system, the large volumes of gas, potentially dangerous, to be purged creates safety problems. The sets of pipework and precision fits are also inclined to leak or to serious damage during use. These installations are therefore not well suited to isolated use requiring frequent disconnection and purge that increase the risks of the operator being exposed to dangerous gases.
Hitherto, the use of gas cabinet devices for distributing specialty gases has revealed that the safety, cost and control downtime are not optimized for isolated applications. These standard gas cabinets can especially be used routinely and reliably for long-term production and distribution applications. These systems are fully installed in large cabinets in dedicated rooms that may lie several tens of meters away from the equipment to which they are connected. When maintenance, calibration, testing or qualification of new sources of ESG for existing methods, evaluation of new methods involving the use of ESG on existing machines, or repair are required, the distribution line may need to be disconnected from a gas cabinet, and may need to remain so for a prolonged period.
As far as laboratories are concerned, because of the high cost of a standard gas cabinet, potentially dangerous gas is distributed sometimes even without a cabinet that has extraction, increasing the risks to the operator, particularly when connecting/disconnecting a cylinder.
There is no distribution device especially devoted to the specific applications mentioned hereinabove and comprising a system that allows it to be fitted to any cylinder without modifying the cylinder. Patent applications EP1316755, EP0916891 and EP1180638 disclose miniature gas distribution systems mounted in place of the standard valve with which a cylinder is equipped. This means that this type of system is specific to the cylinder to which it is fitted and cannot therefore be used on other cylinders. In this regard, it does not meet the requirements of flexibility, mobility, minimum space occupancy and low cost required by the applications at which the present invention is aimed.
The solution hitherto used for distributing specialty gases in laboratories or for the aforementioned applications, is the use of a standard gas cabinet. This gas cabinet may either already be in use for distributing gas to given equipment or procured specially for the purpose.
The use of a standard gas cabinet is ill suited to the specific applications mentioned hereinabove, and that may present risks notably due to the purges and potential disconnections. Specifically, a standard gas cabinet is particularly ill suited to this type of application because of its cost, the amount of space it occupies, its complexity and the constraints involved in bringing it into service, such as the couplings with the equipment. In the microelectronics industry, these kinds of tests can be carried out with the gas cabinet used in production and connected to the machine in which the tests are performed. However, the use of a standard gas cabinet, typically located in a specific room of the production facility, for example entails the purging of long lines of pipework before a new gas cylinder that is to be tested can be connected. In addition, in the microelectronics industry, a distribution device may potentially be used by several items of equipment. Making a distribution device available for isolated applications may entail the needless shutting down of equipment not affected by the tests.
Another solution may be to purchase a standard gas cabinet devoted to this type of test. This solution proves to be very expensive because of the cost of the distribution device and also because of the cost of coupling to the machine. In addition, a standard gas cabinet lives in a set location, and this means that either lines have to be run to all the equipment likely to undergo testing or that the number of these gas cabinets has to be increased. In both instances, the cost of the operation is prohibitively high.
And so, neither the procurement of a standard gas cabinet nor the use of an existing gas cabinet is a solution well suited to this type of application. Further, any equipment used in a clean room has to occupy a very minimal amount of space.
Developing a miniaturized specialty gas distribution device that can be used with any gas cylinder, that is safe, has intelligent automated control, can be used in the silicon industry and more particularly in the microelectronics, photovoltaic, optoelectronics or even semiconductor industry or that can be used in laboratories would constitute significant technological progress. Implementation of a device as innovative as this would meet a long-felt need in such industries.